Peristaltic pump construction

ABSTRACT

A peristaltic pump assembly which utilizes a housing with a circular inner wall to back up a peristaltic tube, and a rotor for progressively squeezing a tube right against that wall. A unique pressure device is utilized on eccentrically mounted pressure rollers in the form of a spring which biases the rollers outwardly against the pump tube with a predetermined resilient pressure. A similar resilient system is utilized for closing the top of the pump which entraps the ingress and egress tubes under resilient pressure.

United States Patent 1191 De Vries 14 1 June 5, 1973 54] PERISTALTIC PUMP CONSTRUCTION 2,393,324 7 1959 1516611 ..417 475 2,958,294 11/1960 Johnson ..417/476 [75] i De Ann Arbor 3,138,104 6 1964 Cantor ..417 477 MlCh. 3,396,669 8/1968 Everett... ....417/476 [73] Assigneez Sums, Inc. Ann Arbor, Mich. 3,644,068 2 1972 Lepak ..417 477 [22] Filed: July 16, 1971 FOREIGN PATENTS OR APPLICATIONS [21] Appl 163,240 603,895 4/1960 Italy ..417 477 Primary ExaminerWilliam L. Freen [52] U.S. Cl ..417/477 Assistant Examiner john winbum [51] Int. Cl ..F04b 43/12 Attorney Barnes Kisselle Raisch & Choate [58] Field of Search ..4|7/474477; 415/201;

92/ l 3.2 [57] ABSTRACT [56] References Cited A peristaltic pump assembly which utilizes a housing 1 with a circular inner wall to back up a peristaltic tube, UNITED STATES PATENTS and a rotor for progressively squeezing a tube right 314 851 3/1885 Ken 7/477 against that wall. A unique pressure device is utilized 513 315 1/1894 Fungi n 0n eccentrically mounted pressure rollers in the form 513 316 1/1894 Funk :.:.:417/476 of a spring which biases the rollers outwardly against 2,018:999 10/1935 De Bakey ..417 477 the P p tube with a predetermined resilient P 2,651,264 9/1953 Bruckmann 417 476 sure. A similar resilient system is utilized for closing 2,679,807 6/1954 Bruckmann ..417/476 the top of the pump which entraps the ingress and 2,789,514 4/1957 Hill ..417/476 egress tubes under resilient pressure.

2,804,023 9/1957 Lee ..417/477 2,865,303 12/1958 Ferrari ..417/475 7 Claims, 5 Drawing Figures PATENIEDJuu 5 I975 SHEET 10F 2 INVENTOR JAM/F5 b. 0.5 Vi /5 BY flux/nu,

ATTORNEYS PERISTALTIC PUMP CONSTRUCTION This invention relates to a Peristaltic Pump Construction and more particularly to a pressure control system for such a pump.

It is an object of the present invention to provide an improved pump construction for a device which is normally motor operated and an improved automatic control for maintaining a radially outward pressure on the pump rollers. Briefly, this is accomplished by biasing the eccentrically mounted roller pins with a coil spring arrangement which urges the rollers outwardly at a predetermined bias.

It is a further object of the invention to provide a pump construction in which there is eliminated any manual roller pressure control to avoid the possibility of an erroneous setting which could cause damage or injury. In the pumping of blood, for example, too much pressure on the rolls against the peristaltic tube can cause damage to the blood cells. The present invention places this pressure under a predetermined bias which cannot be altered by an operator.

A further object is a pump construction with a resilient control of a closing lid for covering the device and simultaneously locating and holding the ingress and egress tubes under predetermined pressure bias.

Other objects and features of the invention relating to details of construction will be apparent in the following description and claims in which the principles of the invention and the operation are set forth in connection with the best mode presently contemplated for the practice of the invention.

Drawings accompany the disclosure and the various views thereof may be briefly described as:

FIG. 1, a top view of a pump incorporating the features of the present invention.

FIG. 2, a front elevation of the pump assembly.

FIG. 3, a sectional view on line 3-3 of FIG. 1 with a staggered section of the rotor to show the roller mount and the guide rollers.

FIG. 4, a bottom view of the rotor on line 44 of FIG. 3 illustrating the 'roller tensioning mechanism.

FIG. 5, an enlarged view illustrating the rotor and roller mount.

REFERRING TO THE DRAWINGS The pump consists of a main housing having a recess in one wall thereof to provide a pump chamber with a circular wall 12. This circular wall blends into tangential walls 14 which terminate at 16. The housing has a rear wall 18 which has a height similar to the side walls around the recess 12 and a front wall 20 which has a lower profile terminating in a top edge 22 (FIG. 2).

A bottom wall 24 is supported by a circular cylindrical housing 26 through which projects a power drive shaft 28 supported by suitable bearings 30. Below the housing 26 is a motor housing 32 which contains a motor connected to the drive shaft 28.

The cover for the housing is formed by a transparent plate 14 which has side ears 36 pivoted by pins 38 extending into the housing 10. The cover may thus be lifted to an open position and dropped down to a closed position over the pumping recess. At the front edge of the cover plate 34 is a cover element 40 having a slot 42 to receive the edge of the plate 34 in tight frictional engagement. The cover element extends thewidth of the housing and has centrally thereof a latch pin 44 which has a threaded end 46 to be received in a threaded hole in the front wall 20 of the housing.

An O-ring 48 on the pin 44 is movable in the recess 50 so that the pin may be shifted up and down. Above the recess 50 is a second recess 52 which houses a spring 54 surrounding the pin and held in place by a head 56 on the pin. Thus, the spring 54 rests on the septum between the recesses 50 and 52 and the parts are so dimensioned that the pin therefor, through the spring, exerts a resilient pressure on the cover elements as they are in the closed position. The front cover element 40 has spaced V-notches 60 which register with similar inverted notches 62 on the front wall 20 of housing 10.

The rotor 64 of the pump is shown in the top view of FIG. 1 as having arm portions 66 carrying pressure rollers 68 and between these rollers are axially spaced guide rollers 70 which position a peristaltic pump tube around the circular wall 12. As shown in FIG. 4, the rollers are mounted on headed screw pins 71. The rotor 64 is mounted on the shaft 28 which is ensmalled at the top to receive a one-way clutch mechanism 72 held in place by a cap 74 and a screw 76. A spacer 77 and the body of cap 74 fit within the central recess of the rotor to guide the parts in assembly and protect the one-way clutch. The one-way clutch mechanism permits manual rotation of the pump in the forward direction for checking; but when power is applied to the shaft 28, it will drive the rotor in the right direction. The one-way clutch can be any standard type of sleeve insert which can create a one-way drive between the shaft 28 and the rotor 64.

In FIG. 5, the rotor 64 is shown in greater detail. The rollers 68 are mounted on pins 80 which have eccentric end mount projections 82 at the top and 84 at the bottom. A flange 86 at the bottom has an annular groove opening to receive a plastic bearing ring 88 and the end projection 84 is mounted in a plastic bearing material 90 recessed in an opening in the rotor 64. On the projection 84 is a control disc 92 which is non-rotatably secured to the projection. Thus, it will be seen that rotation of the pin 80 on the projections 82-84 will cause the roller to move radially relative to the axis of the rotor due to the eccentric relationship. This is controlled by a flat S spring 94, one end of which encircles the control disc 92 and is anchored thereto by a headed pin 96. The other end of the S spring passes around a post 98 positioned toward the center of the rotor, this post having a head portion 100 which provides a retaining shoulder for the spring.

Stop pins 102 and 104 are mounted on the surface of the rotor in the rotative path of the head of the screw 96 so that the mount for the rollers 68 is limited in its rotation. IT will be seen that the springs 96 has a slipping relationship with respect to the posts 98 and they have a bias to tend to unwrap'from the control disc 92. Accordingly, the flat springs tend to move the rollers 68 radially outward to their extreme position but pressure on the rollers will wrap up the spring 94 to some degree against its resilient bias.

It will be noted, as shown in FIG. 3, that the spring control is on the bottom of the roller so that it is not exposed to the top of the pump. Thus, by calibrating the springs 94, a constant pressure can be maintained on the roller 68 against a peristaltic tube mounted in the pump. The power drive is always connected but it is clutch facilitates the insertion of new or replacement tubing in the pump.

It will thus be seen that the above-described 'pump' assembly has a pressure control on the pump'tube which is independent of the operator and similarly the pressure on the tubes as they pass through the front wall of the pump is limited by the spring 54 surrounding the lock pin 44. The pump rotor can be readily removed by loosening the screw 76 and an alternate construction can be utilized wherein an O-ring captures the rotor on the shaft.

I claim:

1. In a peristaltic pump assembly of the type having a housing with a recess and a circular wall forming said recess for positioning a pump tube, and a rotor mounted for rotation within said wall having rollers to contact said tube, that improvement which comprises:

a. a front wall on said housing adjacent said recess having spaced notches to receive respective ends of a tube,

b. a cover element movably mounted on said housing having a wall to position selectively adjacent said front wall, and having spaced notches to register with the notches in said front wall wherein a tube passing through said respective pairs of notches is held captive, the rollers on said rotor being rotatably mounted on mount pins, eccentric end mounts on said mount pins to locate said pins in said rotor wherein rotation of said pin on said mounts will shift the axis of rotation relative to the axis of said rotor, and resilient means operatively associated with one of said end mounts to impart a rotative bias to said pins urging them radially outward.

2. A pump assembly as defined in claim 1 in which one of said end mounts is enlarged to project at one end of said rotor, and said resilient means comprises a flat S spring, one end being coiled around and anchored to said one enlarged end, and post means on said rotor confining'the other end of said S spring.

3. A pump assembly as defined in claim 2 in which said one end of said S spring is anchored to said enlarged end by a headed screw, and stop pins extending from said rotor to limit the rotative movement of said mount pins in each direction, said pins being positioned in spaced relation in the path of rotationof the head on said screw. 7

4. In a peristaltic pump assembly of the type having a housing 'witha recess and a circular wall forming said recess for positioning a pump tube, and a rotor mounted for rotation within said wall having rollers to contact said tube, that improvement which comprises:

a. mount pins for said rollers,

b. eccentric end mounts on said rotor for each end of said mount pins to locate said pins in said rotor wherein rotation of each said'pin on said mounts will shift the axis of rotation of the pin relative to the axis of said rotor, and

c. resilient means operatively associated with one of said end mounts to impart a rotative bias to said pins urging them radially outward toward said circular wall.

5. A pump assembly as defined in claim 4 in which one of said end mounts is enlarged to project at one end of said rotor, and said resilient means comprises a flat S spring, one end being coiled around and anchored to said one enlarged end, and post means on said rotor confining the other end of said S spring.

6. A pump assembly as defined in claim 5 in which said one end of said S spring is anchored to said enlarged end by a headed screw, and stop pins extending from said rotor to limit the rotative movement of said mount pins in each'direction, said pins being positioned in spaced relation in the path of rotation of the head on said screw.

7. In a peristaltic pump assembly of the type having a housing with a recess and a circular wall forming said recess for positioning a pump tube, and a rotor mounted for rotation within said wall having rollers to contact said tube, that improvement which comprises:

a. a front wall on said housing adjacent said recess having spaced notches to receive respective ends of a tube,

b. a cover element movably mounted on said housing having a wall to position selectively adjacent said front wall, and having spaced notches to register with the notches in said front wall wherein a tube passing through said respective pairs of notches is held captive, and

c. means to lock said cover element in a tube retaining position comprising a headed screw captive in said cover and threadable into a threaded recess in said housing, and a spring interposed between said screw and said cover element to exert a predetermined bias on said cover element toward said housing to apply a predetermined pressure to said tube. 

1. In a peristaltic pump assembly of the type having a housing with a recess and a circular wall forming said recess for positioning a pump tube, and a rotor mounted for rotation within said wall having rollers to contact said tube, that improvement which comprises: a. a front wall on said housing adjacent said recess having spaced notches to receive respective ends of a tube, b. a cover element movably mounted on said housing having a wall to position selectively adjacent said front wall, and having spaced notches to register with the notches in said front wall wherein a tube passing through said respective pairs of notches is held captive, the rollers on said rotor being rotatably mounted on mount pins, eccentric end mounts on said mount pins to locate said pins in said rotor wherein rotation of said pin on said mounts will shift the axis of rotation relative to the axis of said rotor, and resilient means operatively associated with one of said end mounts to impart a rotative bias to said pins urging them radially outward.
 2. A pump assembly as defined in claim 1 in which one of said end mounts is enlarged to project at one end of said rotor, and said resilient means comprises a flat S spring, one end being coiled around and anchored to said one enlarged end, and post means on said rotor confining the other end of said S spring.
 3. A pump assembly as defined in claim 2 in which said one end of said S spring is anchored to said enlarged end by a headed screw, and stop pins extending from said rotor to limit the rotative movement of said mount pins in each direction, said pins being positioned in spaced relation in the path of rotation of the head on said screw.
 4. In a peristaltic pump assembly of the type having a housing with a recess and a circular wall forming said recess for positioning a pump tube, and a rotor mounted for rotation within said wall having rollers to contact said tube, that improvement which comprises: a. mount pins for said rollers, b. eccentric end mounts on said rotor for each end of said mount pins to locate said pins in said rotor wherein rotation of each said pin on said mounts will shift the axis of rotation of the pin relative to the axis of said rotor, and c. resilient means operatively associated with one of said end mounts to impart a rotative bias to said pins urging them radially outward toward said circular wall.
 5. A pump assembly as defined in claim 4 in which one of said end mounts is enlarged to project at one end of said rotor, and said resilient means comprises a flat S spring, one end being coiled around and anchored to said one enlarged end, and post means on said rotor confining the other end of said S spring.
 6. A pump assembly as defined in claim 5 in which said one end of said S spring is anchored to said enlarged end by a headed screw, and stop pins extending from said rotor to limit the rotative movement of said mount pins in each direction, said pins being positioned in spaced relation in the path of rotation of the head on said screw.
 7. In a peristaltic pump assembly of the type having a housing with a recess and a circular wall forming said recess for positionIng a pump tube, and a rotor mounted for rotation within said wall having rollers to contact said tube, that improvement which comprises: a. a front wall on said housing adjacent said recess having spaced notches to receive respective ends of a tube, b. a cover element movably mounted on said housing having a wall to position selectively adjacent said front wall, and having spaced notches to register with the notches in said front wall wherein a tube passing through said respective pairs of notches is held captive, and c. means to lock said cover element in a tube retaining position comprising a headed screw captive in said cover and threadable into a threaded recess in said housing, and a spring interposed between said screw and said cover element to exert a predetermined bias on said cover element toward said housing to apply a predetermined pressure to said tube. 